Culture also enables coordination in a different way, by establishing norms and conventions that regulate behavior. Some of these norms are explicit and bear the force of law. We drive on the right- hand side of the road because it’s easier to have a rule that everyone follows rather than to have to play the guessing game with oncoming drivers. Bumping into a fellow pedestrian at the crosswalk is annoying, but smashing into an oncoming Mercedes-Benz is quite another thing. Most norms are 1ongstanding, hut it also seems possible to create new forms of behavior quickly, particularly if doing so solves a problem. The journalist Jonathan Rauch, for instance, relates this story about an experience Schelling had while teaching at Harvard: “Years ago, when he taught in a second-floor classroom at Harvard, he noticed that both of the building’s two narrow stairwells—one at the front of the building, the other at the rear—were jammed during breaks with students laboriously jostling past one another in both directions. As an experiment, one day he asked his 10:00 AM class to begin taking the front stairway up and the back one down. ‘it took about three days,’ Schelling told me, ‘before the nine o’clock class learned you should always come up the front stairs and the eleven o’clock class always came down the back stairs—without, so far as Schelling knew, any explicit instruction from the ten o’clock class. ‘I think they just forced the accommodation by changing the traffic pattern,’ Schelling said.” Here again, someone could have ordered the students to change their behavior, but a slight tweak allowed them to reach the good solution on their own, without forcing anyone to do anything.

Conventions obviously maintain order and stability. Just as important, though, they reduce the amount of cognitive work you have to put in to get through the day. Conventions allow us to deal with certain situations without thinking much about them, and when it comes to coordination problems in particular, they allow groups of disparate, unconnected people to organize themselves with relative ease and an absence of conflict.

Consider a practice that’s so basic that we don’t even think of it as a convention: first-come, first-served seating in public places. Whether on the subway or a bus or in a movie theater, we assume that the appropriate way to distribute seats is according to when people arrive. A seat belongs, in some sense, to the person occupying it. (In fact,in some places—like movie theaters—as long as a person has established his or her ownership of a seat, he or she can leave it, at least for a little while, and be relatively sure no one will take it.)

This is not necessarily the best way to distribute seats. It takes no account, for instance, of how much a person wants to sit down. It doesn’t ensure that people who would like to sit together will be able to. And it makes no allowances—in its hard and fast form—for mitigating factors like age or illness. (In practice, of course, people do make allowances for these factors, but only in some places. People will give up a seat on the subway to an elderly person, but they’re unlikely to do the same with a choice seat in a movie theater, or with a nice spot on the beach.) We could, in theory, take all these different preferences into account. But the amount of work it would require to figure out any ideal seating arrangement would far outweigh whatever benefit we would derive from a smarter allocation of seats. And, in any case, flawed as the first-come, first-served rule may be, it has a couple of advantages. To begin with, it’s easy. When you get on a subway, you don’t have to think strategically or worry about what anyone else is thinking. If there’s an open seat and you want to sit down, you take it. Otherwise you stand. Coordination happens almost without anyone thinking about it. And the convention allows people to concentrate on other, presumably more important things. The rule doesn’t need coercion to work; either. And since people get on and off the train randomly, everyone has as good a chance of finding a seat as anyone else.

Still, if sitting down really matters to you, there’s no law preventing you from trying to circumvent the convention by, for instance, asking someone to give up his seat. So in the 1980s, the social psychologist Stanley Milgram decided to find out what would happen if you did just that. Milgram suggested to a class of graduate students that they ride the subway and simply ask people, in a courteous bit direct manner, if they could have their seats. The students laughed the suggestion away, saying things like, “A person could get killed that way.” But one student agreed to be the guinea pig. Remarkably, he found that half of the people he asked gave up their seats, even though he provided no reason for his request.

This was so surprising that a whole team of students fanned out on the subway, and Milgram himself joined in. They all reported similar results: about half the time, just asking convinced people to give up their seat. But they also discovered something else: the hard part of the process wasn’t convincing the people, it was mustering the courage to ask them in the first place. The graduate students said that when they were standing in front of a subject, “they felt anxious, tense, and embarrassed.” Much of the time, they couldn’t even bring themselves to ask the question and they just moved on. Milgram himself described the whole experience as ‘wrenching.” The norm of first-come, first-served was so ingrained that violating it required real labor.

The point of Milgram’s experiment, in a sense, was that the most successful norms are not just externally established and maintained. The most successful norms are internalized. A person who has a seat on the subway doesn’t have to defend it or assert her right to the seat because, for the people standing, it would be more arduous to contest that right.

Even if internalization is crucial to the smooth workings of conventions, it’s also the case that external sanctions are often needed. Sometimes, as in the case of traffic rules, those sanctions are legal. But usually the sanctions are more informal, as Milgram discovered when he studied what happened when people tried to cut into along waiting line. Once again, Milgram sent his intrepid graduate students out into the world, this time with instructions to jump lines at offtrack betting parlors and ticket counters. About half the time the students were able to cut the line without any problems. But in contrast to the subway—where, when people re fuse to give up their seat they generally just said no or even re fuse to answer—when people did try to stop the line cutting, their reaction was more vehement. Ten percent of the time they took some kind of physical action, sometimes going so far as to shove the intruder out of the way (though usually they just tapped or pulled on their shoulders). About 25 percent of the time they verbally protested and refused to let the jumper in. And 15 percent of the time the intruder just got dirty looks and hostile stares.

Interestingly, the responsibility for dealing with the intruder fell clearly on the shoulders of the person in front of whom the intruder had stepped. Everyone in line behind the intruder suffered when he cut the line, and people who were two or three places be him would sometimes speak up, but in general the person who was expected to act was the one who was closest to the newcomer. (Closest, but behind: people in front of the intruder rarely said anything.) Again, this was not a formal rule, but it made a kind of intuitive sense. Not only did the person immediately behind the intruder suffer most from the intrusion, but it was also easiest for him to make a fuss without disrupting the line as a whole.

That fear of disruption, it turns out, has a lot to do with why it’s easier to cut a line, even in New York, than you might expect. Milgram, for one, argued that the biggest impediment to acting against line jumpers was the fear of losing one’s place in line. The line is, like the first-come, first-served rule, a simple but effective mechanism for coordinating people, but its success depends upon everyone’s willingness to respect the line’s order. Paradoxically, this sometimes means letting people jump in front rather than risk wrecking the whole queue. That’s why Milgram saw an ability to tolerate line jumpers as a sign of the resilience of a queue, rather than of its weakness.

A queue is, in fact, a good way of coordinating the behavior of individuals who have gathered in a single location in search of goods or a service. The best queues assemble everyone who’s waiting into a single line, with the person at the head of the line being served first. The phalanx, which you often see in supermarkets, with each checkout counter having its own line, is by contrast a recipe for frustration. Not only do the other lines always seem shorter than the one you’re in—which there’s a good chance they are, since the fact that you’re in this line, and not that one, makes it likely that this one is longer—but studies of the way people perceive traffic speed suggest that you’re likely to do a bad job of estimating how fast your line is moving relative to everyone else’s. The phalanx also makes people feel responsible for the speed with which they check out, since it’s possible that if they’d picked a different line, they would have done better. As with strategizing about the subway seat, this is too much work relative to the payoff. The single-file queue does have the one disadvantage of being visually more intimidating than the phalanx (since everyone’s packed into a single line), but on average everyone will be served faster in a single queue. If there’s an intelligent way to wait in line, that’s it. (One change to convention that would make sense would be to allow people to sell their places in line, since that would let the placeholders trade their time for money—a good trade for them—and people with busy jobs to trade money for tine—also a good trade. But this would violate the egalitarian ethos that governs the queue.)

At the beginning of this chapter, I suggested that in liberal societies authority had only limited reach over the way citizens dealt with each other. In authority’s stead, certain conventions—voluntarily enforced, as Milgram showed, by ordinary people—play an essential role in helping large groups of people to coordinate their behavior with each other without coercion, and without requiring too much thought or labor. It would seem strange to deny that there is a wisdom in that accomplishment, too.